Water turbine bucket construction



March 1, 1960 J. HERTRICH WATER TURBINE BUCKET CONSTRUCTION OriginalFiled April 6, 1954 3 Sheets-Sheet 1 INVENTOR AT ORNEY5 March 1, 1960 J.HERTRICH WATER TURBINE BUCKET CONSTRUCTION Original Filed April 6, 19543 Sheets-Sheet 2 v IIIIII/ /I III II l/ll/I/ March 1, 1960 J. HERTRICH2,926,886

WATER TURBINE BUCKET CONSTRUCTION Original Filed April 6, 1954 3Sheets-Sheet 3 J a 11 r "2.135 ed 5 fizei arwwazk P W ATTORNEYS UnitfiidStates Patent 2,926,386 7 WATER TURBINE BUCKET CONSTRUCTION JosephHertrich, deceased, late of Hamilton, Ohio, by E i Hertrich, executrix,H mi ton, Oh ss ns: to The Western States Machine Company, Hamilton,.Qhi.0, a corporation of Utah. l

Original application April. 6, 1954, Serial No. 421,383. ?0li'lgt4l andthis application April 6, 1955, Serial No- '4 Claims. (Cl. 253-26) Thisapplication is a division of applicants copending application Serial No.421,383, filed April 6, 1954.

This invention relates to new and useful improvements in centrifugalmachinesand particularly to suspension and driving means for gyratorycentrifugals of the type commonly used for the manufacture of sugar.

The invention is particularly adapted for the improve ment ofturbine-driven centrifugal machines, but various features of itsconstruction and operation may be used to advantage for other types ofsuspended gyratory cen-- trifugal machines.

An important object of this invention is to provide an improvedconstruction ofthe buckets of a hydraulic tunbine wheel of thePeltonWheel type, by which the energy of an impinging water jet will beabsorbed with high efliciency in the operation of the wheel.

Another object is to provide a bucket construction which utilizes amaximum part of. the working surface of the bucket for absorbing energyfrom the jet while pro? viding for the positive free discharge of thespent water from each bucket. t

An impulse bucket constructed according to this invention comprises abowl portion longer in the radial direc, tion than it. is wide, thefront open side of the bowl portion presenting at its lower part a freeperipheral edge lying in a radial plane from. the axis of the wheel. The

upper part of the bowl portion has an extension formed as an overhanginglipportion that slopes upwardly and forwardly so as to terminatesubstantially forward of the free peripheral edge- The lip portion andthe merging inner surface of the bowl portion form at the outer upperpart of the bucket a jet impingement surface to receive a water jet anddeflect it into and thence from the base of the bowl portion fordischarge over the lower free peripheral edge. t

Other objects, features and advantages of this invention will beapparent from the following detailed description of an illustrativeembodiment and from the accompanying drawings thereof.

In the drawings:

Fig. l is a vertical section through an illustrative embodiment of thisinvention with the basket broken away and showing the turbine Wheelpartially in side elevation and partially in section;

Fig. la is a horizontal cross-section taken along line 1a- -1a of Fig.1;

Fig. 2 is a diagrammatic plan view of the water wheel and turbinenozzles, showing the relative positions of the nozzles to the wheel; r

Fig. 3 is a longitudinal cross-section'through; a water supply controlvalve used in the embodiment of Fig.1;

Fig. 4 is a fragmentary perspective view of a preferred form of waterwheel, showing positions of the buckets assembled on the hub of thewheel;

Fig. 5 is an elevation of a single bucket looking into the bowl of thebucket;

Fig. 6 is a plan view of the bucket of Fig. 5

Fig. 7 is an end elevation "of the bucket looking at the radially outerendthereof;

Fig. 8 is a transverse crass-sectional view of the bucket taken alongline 8-8 of Pig. 5;

Fig. 9 is a longitudinal horizontal sectional view of the u k t takenalong l n 9 9 of Fig,-

Figs. 10 and ll are fragmentary cross sectional views of the bucket.taken at oblique angles along lines 10TH) and 11* 11, respectively, ofFig, 5 to: show the contours of lower portions of the bucket;

Fig. 12 is an elevation similar to Fig. 5, provided with contour linesto. illustrate the shape of the bucket more le r y; nd

Figf13 is a horizontal longitudinal section taken on the longitudinalmedian line of the bowl portion, looking upwardly toward the top of thebucket and showing by contour lines the shape of the upper part. of thebucket.

Referring first to Fig. l, a usual perforate centrifugal basket 10 isdisposed within a surrounding; curb or casing 12. and is rotatablycarried by a suspended spindle 11 for rotation therewith. The spindle issuspended by a suspension head, indicated generally at 13, from. astationary hanger 14 which carries the weight of the basket and spindleThe spindle 11 is formed in two separate sections 11a and 11b which arebolted together by bolts 11c that extend through bores in flanges 15 and16 formed externally on sections 11a and 11b, respectively. a The lowersection carries the basket, and the upper section is conneeted through aflexible coupling 17 with the lower end of a vertically disposed driveshaft 18, to which is secured the impulse wheel 19 of a water turbine20. This wheel is enclosed within a water housing 21, the base of whichrests on conventional supporting framework The stationary hanger 14 isformed with an integral external flange 22 by which it is bolteddirectly to the base of the water housing 21, as at 23.

A centrifugal brake drum 24 is detachably secured directly tothe'spindle for rotation therewith and surrounds the suspension headassembly, extending axially in concentric spaced relation thereto. Drum24 is bolted to the spindle by bolts 25 which extend through alignedbores in a flange 26 formed internally on the drum and overlappingllange 15 of spindle section 11a. The drum is arranged to be engaged byfriction brake bands 27 supported from hanger rods 27:: in known manner.

A non-rotary hollow sleeve 28 surrounds the upper section 11a of spindle11 and has an upward extension 41 that surrounds and extends to alocation above the flexl plin n pa ed re a ion thereto he adia andthrust loads on the spindle 11 are transmitted d i reetly from thespindle to the sleeve 23 by vertically spaced sets of bearings 29 and30, which are disposed between the spindle and the sleeve.

The upper bearings 29 are preferably a double set of radial and thrustball-bearings having their inner races seated on a cylindrical portionof spindle section 11a, over shoulder 33 thereof, and their outer racesresting against cylindrieal portion 31 of sleeve 28 on an upwardlyfacing shoulder 32 of. the leeve, and a. nut 34 threaded; on the spindleseetion bears downwardly against the inner races so as to hold the.bearings firmly in working position. A ring or cap 35 overlies thethrust bearings and is provided with passages 36 to direct lubricatingfluid to the bearings from an oil chamber formed by the sleeve Uextension 41. The ring 35 is confined axially between the nut 34 and theupper outer race of the bearings.

The lower bearings 30 comprise a set of self-aligning roller bearingsdisposed at the lower end of the gyratory sleeve 28 between opposingcylindrical portions of the sleeve and spindle 11a. The inner race abutsan annular collar 37 held between it and an enlarged spindle portion 38below the collar.

An enlarged portion of the gyratory sleeve just below the extensionsurrounding flexible coupling 17 is formed with aconvexly sphericalsurface or ball element 39 that fits into a complementary concavelyspherical, upwardly facing surface 40 of a stationary annular ring orsocket element 40a. Socket element 40a is supported by the stationaryhanger 14. It will be understood that the ball and socket arrangement39-40 supports the assembly of the sleeve 28, while permitting thisassembly to gyrate about the center point C of the ball and socketelements in response to unbalanced basket loads or changes of basketload distribution which occur in the operation of the machine. r

A Apositive drive connection is provided between the non-gyratoryturbine drive shaft 18 and the gyratory basket spindle extension 11a bymeans of the flexible coupling 17 which permits the necessaryoscillatory movements of the spindle assembly about the center ofgyration at C, and this same coupling is here made to serve also as aradial antifriction bearing for the lower end of the drive shaft so asto eliminate the need for a ball or roller hearing at that location.Coupling 17 is disposed at the level of the center of gyration. Itcomprises a collar 44 fixed to the upper end of spindle section 11a andhaving a circular series of radial teeth 45 which are evenly spacedapart and are fitted between the spaced axially extending teeth 43a of adriving ring 43b fixed to the lower end of the turbine shaft 18. Theteeth 45 of the gyratory collar 44 are crown teeth whichhave convexlateral surfaces engaging the adjacent flat surfaces of the teeth 43a onring'43 and convex outer surfaces to engage the inner face of a sleeve46 which is fixed to ring 43 in surrounding relation to the series ofinterfitting teeth 45 and 43a. The sleeve 46 serves to restrict orprevent lateral displacement of the axis of the turbine shaft relativeto the axis of spindle section 11a at the center of gyration while stillpermitting the needed gyratory movement of the spindle assembly in thecourse of the centrifugal operations. By this construction, the flexiblecoupling serves not only to transmit torque from the turbine to thespindle but also acts as an antifriction radial bearing to sustain thelateral or radial loads acting on the lower end of the turbine shaft.Swinging movement of the basket and spindle assembly away from thenormal axis of rotation is resisted by a-resilient buffer ring 42,preferably made of rubber, which is disposed at a level above the centerof gyration C and is confined between an upwardly and outwardly facingseat formed by flanges 47 and48 at the top of sleeve extension 41 and anoppositely facing seat formed by an inner cylindrical surface of hanger14 and an overhanging annular plate 49 which is movably fastened to thehanger by bolts 49a. The buffer ring 42 affords the desired yieldingresistance to the gyratory movements of the basket and spindle assembly,and the degree of this resistance can be adjusted by adjusting the platefastening bolts 49a, or by substituting a different buffer ring belowplate 49, without dismounting the head of the machine. A cover or shield78 on shaft 18 overlies a central opening 49b in plate 49, through whichthe coupling ring 43 may be lifted freely whenever it is desired toremove the housing 21 and the driving motor from the machine.

Further in accordance with this invention, the suspension head isprovided with means for maintaining a continuous forced circulation ofoil through its bearings and over other rubbing parts for simultaneouslylubricating and cooling the same, and the same head is provided 4 o withmeans for cooling the surrounding friction brake drum 24 with aregularly replenished body of cooling water. As shown in Fig. 1, an oilinlet port 60 is formed in the side wall of hanger 14 to deliverlubricating oil fed through a conduit 61 into an annular chamber 51formed inside the hanger between its side and the inwardly spaced upwardextension 41 of sleeve 28. A concentric chamber 50 is formed at theinner side of extension 41 in surrounding relation to the flexiblecoupling 17. A radially extending passage 53 in extension 41 connectschamber 50 with chamber 51 so that oil fed into the latter through port60 will overflow into chamber 50 and can be maintained at a levelinundating the working surfaces of the coupling 17. I

It will be seen that the space between the spindle section 11a and thegyratory'sleeve 28 not only provides clearance to accommodate the upperand lower bearing sets 29 and 30 but also contains between thesebearings an annular partition 58 which defines inner and outer passages54 and 55, respectively, for the circulation of lubricating oil. Axiallyspaced flanges 56 and 57 on the inside of the gyratory sleeve 28 supportand are sealed to the upper and lower ends of the partition. Thus thepartition 58, sleeve 28 and spindle 11a form an inner annular passage 54through which oil passes from the upper bearings to the lower bearings,and between the partition and sleeve 28 there is a separate annularpassage 55 through which used oil may be returned to the oil supplysystem (not shown) in a manner yet to be described.

It will be evident that oil present in chamber 50 of the sleeveextension will flow by gravity through passages 36 of the upper bearingcap 35, will then bath all the parts of the upper bearings 29, and thenwill flow through the inner annular passage 54 to inundate moving partsof the lower bearings 30.

As the oil leaves the lower bearings it passes into an oil reservoirwhich is formed around the lower portion of sleeve 28 by means of anannular wall 59 secured to an upper surface of the flange 15 of spindlesection 11a. Wall 59 is spaced inwardly from the friction drum 24 andspaced outwardly from sleeve 28, and it extends upwardly from flange 15in that spaced relationship to a suitable location where a top wall 59aextends inwardly from wall 59 to 'form a running seal with the outerperiphery of sleeve 28. This seal is formed by an inward flange 59b ,ofwall 59a extending into the confines of an outwardly facingannular'groove 59c insleeve 28. An annularshieldor. cap 59d is fitted onsleeve 28 above wall 59a and extends over that wall and around it andthe uppermost part of wall 59 so as to prevent cooling water inside thebrake drum 24 from entering into the oil reservoir formed by wall 59.

,The oil flowing past the lower bearings at 30 thus accumulates in theoil reservoir surrounding these bearings, and as the machine is operatedexcess oil is regularly removed from the oil reservoir by the action ofa stationary scoop 62 which is fitted into a radial opening in sleeve 28and has an oil passageway 62a for conducting oil from the reservoirformed by wall 59 into the outer oil passage 55 formed between sleeve 28and partition 58. As shown more fully in Fig. 1a, the scoop 62 has amouth disposed in the path of movement of oil which rises on and rotateswith the inner surface of wall 59 as the machine rotates at high speed.Since the mouth opens in a direction opposite to the direction ofrotation, oil on the rotating wall 59 is scooped therefrom and flowsunder pressure through port 62a into annular passage 55. When passage 55is filled with oil, the excess oil may be discharged throughcommunicating ducts 64, 63 and 65, which extend through sleeve 28, ring40a and hanger 22 into bore 66 or a fitting 71 connected by pipe 72 witha suitable oil cooling and supply system not shown A suction pumppreferably is connected with pipe 72to assure the continued removal ofused oil accumulated in. passage 55.

The excess oil in the head may be discharged by gravity, if desired, inwhich event fitting 71 may be removed and the hanger opening closed by apipe plug screwed in the place of this fitting; Duct then opens into anupright duct 67 in hanger 14, which opens into an overflow pipe locatedat the desired maximum level of oil in the chambers 50 and51. In thisarrangement, the feed pipe 61 has a shut-off valve, preferablysolenoid-operated, which will stop the inflow through pipe 61 Wheneverthe machine stops, i.e., whenever the scoop 62 ceases to be active dueto insuflicient rotation of reservoir wall 59. In this manner of use ofthe structure, oil pumped upward by the scoop action flows through duct67 and is discharged by gravity through the overflow pipe 70. By reasonof port 67a between chamber 50 and chamber 51, the duct 67 and overflowlubricating oilis circulated in a positive manner by ad j mitting oilinto a stationary part of the head (the hanger),

passing the oil by gravity to upper and lower bearings I supporting therotating parts of the assembly, and then forcibly returning the oil byself-contained means in the head to the stationary hanger for return tothe oil cooling and supply system and subsequent recirculation throughthe head.

A regulated circulation of brake cooling water also is maintained duringoperation of the machine, the supply of this water being introduced intothe brake drum 24- through inlet pipe 76 and excess water being removedfrom the inner surface of the drum in the running phase of eachcentrifugal cycle by the action of a scoop-like end of discharge pipe77. During the running phase, the water walled up against the drum is.prevented from overflowing by top flange 24a on the drum and by thescooping action of pipe 77 When the machine is stopped, the water supplythrough pipe 76 is stopped by the operation of a suitable shut-off valve(not shown). The shield and sealing devices at 59b,.c and d not onlyprevent water inside the drum from reaching the oil inside wall 59 butalso prevent this oil from spilling into the space for the coolingwater.

With the described head and drive arrangement, the brake is convenientlydisposed on the spindle between the driving means and the basket .of themachine and near. the center of gyration ofthe spindle and basketassembly, and all parts of the suspension head as well as the flexiblecoupling, the brake elements, and the feed and discharge lines forlubricating oil and brake intercepting a water jet will first cut evenlyinto the jet cooling water are organized together in a compactarrangement which is relatively easy to assemble and disassemble andwhich makes optimum use of the limited. head room normally available atthe machines.

In association with the structure described above, a driving system isprovided for the gyratory basket and spindle assembly having newfeatures of construction and control which give important operatingadvantages. With reference to the driving unit. 20 of Fig. 1, theimpulse or water wheel 19 within housing 21 has a hub to the peripheryof which is fixed a set of. spaced impulse buckets 200. A pair ofnozzles 103 and 104 are spaced apart and arranged in the housing so asto direct separate jets of water against the buckets 200 atdiametrically opposed parts of their orbit. At its lower end the housing21 is provided with an outlet 106 through which water is discharged fromthe housing. An inner casing 107 surrounds the turbine shaft 18 belowwheel 19 and slopes downwardly and outwardly to the base of the housingso as to close off the interior of thewwater housing from the upper endof the flexible coupling and .head assembly.

ing that direction.

The impulse wheelbuckets 260 have. the function of extracting energyfrom the water jets discharged from nozzles 103 and .104 so as to drivethe wheel and the shaft and spindle connected with it. As shown moreparticularly in Figs. 4 to 13, the wheel 19 comprises a large number ofthese buckets arranged symmetrically about its axis in a uniformlyspaced relation, and each of the buckets has a distinctive bowlconstruction which is formed to intercept the free water jets and todischarge the'water from the jets in a manner giving a very high powerefficiency along with freedom from energy losses commonly caused by thedischarge. of water from known impulse wheel buckets into the path ofrotation of the wheel.

Each of the buckets is attached to the hub 100 by means of an inwardlyextended mounting lug 205 which is integral with an upper inner part ofthe bucket. The lug 205 has a flat and wedge-shaped horizontal outlinewhich adapts it to fit on the hub in close relation to the lugs ofadjacent buckets, and each lug is fastened securely to the hub by screws206.

Each bucket 200 comprises an approximately semiellipsoidal bowl portion201 that is longer in the radial direction than it is wide and isdisposed in an upright radial position with its closed side or basefacing the direction of wheel rotation and its open side or front trail-At the lower part of its front side each bucket has a front peripheraledge 202 that lies in a radial plane from the axis of the wheel 100. Theupper part of the bowl portion extends into an upwardly and forwardlysloped lip portion 203 which is spaced above and forward from the planeof said front pe ripheral. edge 202 and which terminates at an extremeforward point 203a near the transverse vertical median line of the bowlformation. The upper and outer quadrant of the bucket forms a. jetimpingement surface 204 which is constituted in part by an outer part ofthe lip portion 203 and in part by the merging inner surfaceof the upperpart of the bowl portion. This. jet impingement surface. receives theWheel energizing water jet and deflects it into and thence from the baseof the bowl portion for discharge over the front peripheral edge 202.

The jet impingement surface 204 terminates at'the outer limit of thebucket in a sharp edge 209 that slopes upwardly and forwardly to acorner 210 at the top of the bucket, which'corner is located near theplane of the lower edge 202. The edge 209 is so formed that it lies in avertical plane substantially tangent to the orbit of the water Wheel.Accordingly, as may be seen from Figs. 2, 4 and 5, when the wheel isrotating the vertical edge 209 of the jet impingement surface of eachbucket on a vertical line, allowing the unintercepted part of the jet tocontinue impinging on a bucket ahead, and as the wheel brings theintercepting bucket more. nearly normal to the jet, the place of jetimpingement moves inwardly along sloped surface 204, with the center ofthe jet approximately on the broken line A of Fig. 5, until a finalimpingement position indicated by broken circle B of Fig. 5 is reached.The jet then begins to be intercepted by a following bucket.

As may be seen in Figs. 8, l0 and 11, the lower edge portion or lip ofthe bucket leading to the front peripheral edge 202 is flared slightlyso as to direct the liquid discharged from one bucket in a path free andclear of the next succeeding bucket. As shown in Figs. 5 and 12, thefront peripheral edge 2.02 of each bucket extends in an approximatelyelliptical form to end portions which lie above the horizontal medianline of the bowl portion tinned motive power.

the inner end of the bowl portion, the front peripheral edge 202terminates in a sharp corner 213 from which a downwardly facing inneredge 214 of the bucket extends forwardly and substantially horizontallyto a lower inner corner 215 of the lip portion 203. From corner 215 theface of the upper inner portion of the bucket merges with the forwardside of lug 205 and slopes forwardly and outwardly, as seen at 216 inFigs. and 8, to the forward point 203a of lip portion 203. From thatpoint a backwardly and outwardly curved edge 217 extends to the upperouter corner 210 of the bucket structure.

As already mentioned, the jet issuing from each of the nozzles 103 and104 is initially intercepted bythe cutting edge 209 of each bucket asthe impulse wheel rotates. The shape of the bucket formation and theslope of the jet impingement surface 204 are such that water firstimpinging on that surface is diverted inwardly and downwardly throughthe ellipsoidal bowl portion to be discharged over the free peripheraledge at 202. The bucket then is disposed at a considerably obtuse anglewith respect to the jet. As this angle diminishes the jet impingementsurface takes the full flow and force of the jet and the water isdiverted more abruptly downwardly into the bowl portion, which absorbsfully the energy available from the jet, but the discharge of the spentwater still takes place downwardly over the free edge 20?. in a pathclear of other buckets on the water wheel.

In this way all the water of the jet is discharged on the lower side ofthe wheel 100, thereby eliminating the energy losses that result fromthe usual wash of considerable quantities of discharged water back overthe wheel and the buckets. It will also be evident that the presentconstruction utilizes a maximum part of the working surface of thebucket for absorbing energy from the jet while providing for thepositive free discharge of the spent water from each bucket.

Control of the power developed by the water turbine for bringing thecentrifugal machine to the desired full operating speed is effected bywater flow control valves 117 and 117a which respectively regulate thewater flow through nozzles 103 and 104. To provide the high powernecessary for acceleration of the machine, both nozzles are opened todirect two separate jets against the wheel. When the full speed isreached either of the nozzles may be closed to continue the full speedoperation under the reduced power of the jet from the other nozzle, orboth of the nozzles may be closed so as to allow the machine to coast athigh speed without can The control valves are pressure responsive quickacting valves which are particularly suitable for remote control bysuitable automatic control means.

The nozzles 103 and 104 are mounted in the ends of respective housings116 and 116a which form water passages 1-15 and 115a extending from therespective control valves 117 and 117a. Each nozzle housing isdetachably supported as a removable segment of the water housing 21 sothat it can easily be removed and replaced in order to substitute anozzleof different size, or for any other reason.

The control valves 117 and 117a are identical in construction andoperation, so the details of only one of these are shown in Figs. 1 and3 of the drawings. As seen in Fig. 3, valve 117 includes an elongated,hollow, valve body 118 having an inlet 119 at one end, an axiallyaligned outlet 120 at the other end and a water chamber 118a between theends. Outlet 120 is defined by a replaceable, wear-resistant ring 121that forms an annular seat 121a for the conical tip 122b of an axiallyreciproeable valve needle 122. A substantially cylindrical needlehousing 123 is disposed within and on the axis of the valve body 118 inspaced relation to the surrounding Wall of the water chamber, housing123 being supported in' that position by ribs 124 extending from thechamber wall. The needle housing forms an elongated cylindrical chamber125 which is open at its end nearer to outlet and which slidablyreceives needle 122 through the open end. A lining 126 forms the innerwall of chainher 125, and a rear end wall of this chamber is formed by aplate 128 which constitutes a spring seat having an aperture 128a toconnect chamber with a cavity 127 in the rear end of housing 123a. Thecylindrical stem or plunger 122a of the needle is sealed against theinner cylindrical surface of lining 126 and is provided with a series ofexternal grooves 132 which assist the sliding and sealing actions of theneedle.

The needle 122 is formed with an axial cavity 130 that opens from itsrear end into chamber 125 and receives a compression spring 131 bearingagainst the plate 128. The spring serves to move the needle to itsclosed position against the valve seat under circumstances hereinafterdescribed.

The pressure of water in chamber 118a of the valve body 118-can betransmitted into chamber 125, for ap plying pressure to the back ofneedle 122, through a pilot valve indicated generally at 129, a duct 135leading into the pilot valve from chamber 118a, and a duct 136 leadinginto cavity 127 from the pilot valves The pilot valve 129 includes avalve body 140 having therein a chamber which communicates with duct 135through port 146 and a filter plug 161 and communicates with duct 136through a port 147 containing a restricted passageway or bleeder 155 forlimiting the rate of water flow into and from the needle housing. Thewall of chamber 145 opposite to port 146 has an outlet opening 151 whichnormally is closed'by a movable valve needle 144 held against the mouthof this opening by a spring 138. A forward surface 14411 of thesamevalve needle is arranged to open and close the passageway throughport 146 by movement of the needle relative to seal element 143 in port146, the arrangement being such that port 146 is open when port 151 isclosed by needle 144 and port 151 is open when port 146 is closedthereby. When port 151 is open, water can flow freely through it into achamber 149 of the pilot valve body and thence through port 150 at thebottom of 7 admitted into this chamber, and when the pressure againstdiaphragm 137 of air in chamber 139 exceeds the pressure of spring 138,the valve needle 144 is moved from its normal position in which port 151is closed to a position in which port 146 is closed.

Accordingly, the admission of compresed air to the pilot valve throughconduit 160 serves to close the passageways connecting the water chamber118a with the main needle chamber 125 and to release through bleeder 155and port 151 any water pressure existing in chamber 125, while theventing of air pressure from the pilot valve serves to interconnectchamber 118a and chamber 125 so that the pressure of water in the formerwill be transmitted into the latter and thus will be applied to the rearend of the plunger 122a of needle 122. It results that in the normalposition of the pilot valve, the full water pressure being applied tothe rear end of the valve needle 122, this pressure together with theforce of the spring 131 will move needle 122 to its closed positionwhere the needle will be held as long as the pilot valve stays in normalposition thus preventing the passage of water to the nozzle 103 or 104of the impulse wheel.

It will be noted further, however, that the plunger portion 122a ofneedle 122 terminates at a forwardly an inch,away from seat 121a.

facing shoulder 134 on, a, forward part of this needle within waterchamber 118a. This shoulder presents a sufficient area that the backwardpressure exerted against ityby the water present in chamber 118a,substantially exceeds the forward seating force exerted on needle 122 bythe weight of the needle and/or by the compression spring 131 when theneedle is in its seated position. Accordingly, when the pilot valve 129is moved from its normal closed position to its other or activeposition, the water pressure normally applied against the back end ofneedle 122: is released from chamber 125, and the backward pressurestill exerted on shoulder. 134 then moves needle 122 away from itsseated position. To facilitate this unseating movement, the spring 131may be made or arranged so that it exerts little or no force until theneedle has moved a substantial distance, say A; of As the needle movesto open port 120, the conical end surface 122b also becomes subject tothe pressure of the water supply; so this pressure continues to move theneedle backward against spring 131 until the valve is fully open. waterin chamber 118a then flows under its full pressure through port 120 andpassage 115 or 115a to form a wheel-driving jet as it issues from thewater nozzle 103 or 104.

If any failure occurs in the supply of air pressure for the pilot valve,the corresponding water jet driving the machine is automatically cut offby action of the control valve, due to the release of air pressure fromchamber 139 and the resulting closing movement of needle 122.

In the use of the disclosed machine, the inlet 119 of each control valveis connected with a source of water held constantly under a pressuresuitable for driving the water turbine, and the compressed air line 160of each valve is connected through a suitable air valve, for example, ahand operated or solenoid-operated three-way air valve, with a source ofair held constantly under a pressure sutficient to overbalanc'e thepilot valve spring 138. When a solenoid-operated air valve is used, itmay be actuated by electrical control means of a type widely used forcontrolling the operations of sugar centrifugals.

If the machine is to be used with a mechanical discharger fordischarging solids from the centrifugal basket, the drive shaft 18preferably is extended above the water wheel, as indicated at 250 inFig. 1, so as to pass through a top bearing shown at 252 and beconnected with the driven clutch element of a low speed discharge drivemechanism of the type disclosed and claimed in United States LettersPatent No. 2,667,974 of Joseph Hertrich.

The operations of the present machine are carried out in any of the waysused for sugar centrifugals or other heavy cyclical centrifugalmachines. When the basket is ready to be accelerated to its full runningspeed, compressed air is admitted to line 160 of each of the controlvalves 117 and 117a, whereupon the valves open and water jets from thenozzles 103 and 104 impinge against the buckets 200 of the impulsewheel. The machine then accelerates under the energy absorbed from thejets, and when the full running speed is reached at least one of thejets is cut off by releasing the compressed air from the correspondingpilot valve. This can be done manually or by actuating an air valve online 160 by an automatic time-controlled or speed-controlledmechanismtnot shown). Meanwhile, the spent water from the jets leavesthe buckets 200 entirely beneath the water wheel 100 and passes throughchamber 108 of the water housing to the water outlet 106.

When the machine has run for the desired period at high speed, both ofthe water control valves are closed and the brake 27 is applied in knownmanner to bring the machine to rest. During all the running period, oilis fed through pipe 61 into the lubrication system of the head, excessoil is returned to the oil supply tank (not shown) through pipe 70 orpipe 72 cooling water is 20 The fed into the brake drum through pipe"76, and excess water is, discharged from the drum through, scoop pipe77.

It will be understood that each of the several new features andcombinations of this invention, either alone or in combination withother new features here disclosed,

may be embodied. in various forms of apparatus without restriction todetails of the illustrated embodiment.

What is claimed is:

1. A hydraulic impulse turbine wheel comprising a horizontal circularseries of impulse buckets rotatable about a vertical axis by asubstantially horizontal free liquid jet, each of said bucketscomprising a cup-shaped body mounted on a radius from said axis with itsconcave side disposed vertically to face and intersect said jet in apart of its orbit, the concave side of said body comprising a centralbase portion elongated in the direction of said radius, a lower portionextending forwardly from the lower side andthe ends of said base portionwith an approximately ellipsoidal curvature to, and terminating in afree front edge bordering the lower part of said body and lying in avertical plane approximately aligned with said axis, and a forwardly andupwardly sloped upper surface portion extending from the upper side ofsaid base portion to a location near the top of said body, thelast-recited portion forming a sloped jet impingement surface a majorportion of which, near the vertical median line of said body, isdisposed for-- wardly of said plane to receive said jet and deflect itdownwardly in said body for the discharge of spent liquid over saidfront edge.

2. A hydraulic impulse turbine wheel comprising a horizontal circularseries of impulse buckets rotatable about a vertical axis by asubstantially horizontal free liquid jet, each of said bucketscomprising a cup-shaped body mounted on a radius from said axis with itsconcave side disposed vertically to face and intersect said jetin a partof its orbit, the concave side of said body comprising a central baseportion elongated in the direction of said radius, a lower portionextending forwardly from the lower side and the ends of said baseportion with an approximately ellipsoidal curvature to, and terminatingin, a free front edge bordering the lower part of said body and lying ina vertical plane approximately aligned with said axis, and a forwardlyand upwardly sloped upper surface portion extending from the upper sideof said base portion to a. location near the top of said body, saidupper portion extending forwardly in a pointed formation near thevertical median line of said body to form a sloped jet impingementsurface which at that line is predominantly disposed for wardly of saidplane to receive said jet and deflect it downwardly in said body'for thedischarge of spent liquid over said front edge.

- 3. A hydraulic impulse turbine wheel comprising a horizontal circularseries of impulse buckets rotatable about a vertical axis by asubstantially horizontal free liquid jet, each of said bucketscomprising a cup-shaped body mounted on a radius from said axis with itsconcave side disposed vertically to face and intersect said jet in apart of its orbit, the concave side of said body comprising a centralbase portion elongated in the direction of said radius, a lower portionextending forwardly from the lower side and the ends of said baseportion with an approximately ellipsoidal curvature to, and terminatingin, a free front edge bordering the lower part of said body and lying ina vertical plane approximately aligned with said axis, and a forwardlyand upwardly sloped upper surface portion extending from the upper sideof said base portion to a location near the top of said body, thelast-recited portion forming a sloped jet impingement surface a majorportion of which, near the vertical median line of said body, isdisposed forwardly of said plane to receive said jet and deflect itdownwardly in said body for the discharge of spent liquid'over saidfront edge, said front edge having end portions extending upwardly 11 insaid plane in bordering relation to the radially outward and inwardlimits of said body to terminal points iocated substantially above thehorizontal median line of said body.

4. A hydraulic impulse turbine wheel as described in claim 3, each ofsaid buckets comprising also a backwardly cut out portion in the wall ofsaid body forming a jet entrance gap above the outward terminal point ofsaid front edge, the bordering edge of said gap lying in a verticalplane substantially tangent to the outermost circle of the orbit of saidbody and its upper portion being sloped forwardly and upwardly at theoutward limit of said upper surface portion.

References Cited in the file of this patent UNITED STATES PATENTSGfeller Nov. 8, Pfau Dec. 13, Herr Oct. 9, Schmidt Sept. 6, Moody Sept.23,

FOREIGN PATENTS Great Britain Feb. 27, France July 2,

